Evaluation of .Net:
Drawbacks of existing technologies:
1) Platform dependency
2)Language interpretability
3)Distributed application development
4)Cross languageError handling
5)Web application
6)Mobile application development
7)Security
8)Database connectivity
.Net releases:
1 1998 In professional conference Microsoft announced about new environment.
2 2000 Beta version of .Netframework
3 2002 Actual release of .Net framework1.0
4 2003 .Net framework1.1 release
5 2005 Net framework 2.0 released
6 2006 .Net framework 3.0 released
7 2007 .Net framework 3.5 released.
.Net Framework Architecture
NET Framework Architecture
1 .Defination:Net Framework is a common platform for developing various types of applications(windows,web apps..etc) using dotnet compatible languages(VB.Net,C#.Net…etc)
2 NET Framework Architecture has languages at the top layer such as VB .NET C#, VJ#, VC++ .NET;
3 Layer2 has types of application such as Windows Forms, Web Form, Windows Services and XML Web Services.
4 Bottom two layers consist of .NET Framework class library and Common Language Runtime
The .NET Framework has two components: the .NET Framework class library and the common language runtime.
Common Language Runtime
The common language runtime is the foundation of the .NET Framework. CLR act as an agent that manages code at execution time, providing core services such as memory management, thread management, and remoting, while also enforcing strict type safety and facilitates with code accuracy that ensure security and robustness
.Net Framework class library::
The class library, is a integral component of the .NET Framework, consists of object-oriented collection of reusable classes (types) that we can use to develop applications ranging from traditional command-line or any graphical user interface (GUI) applications such as Windows Forms, ASP. NET Web Forms and Windows Services the newly invented XML Web services
Types of applications:
1)Console applications are light weight programs run inside the command prompt (DOS) window. They are commonly used for test applications.
2)Windows Applications are form based standard Windows desktop applications for common day to day tasks. Microsoft word is an example of a Windows application.
3)Web applications are programs that used to run inside some web server (e.g., IIS) to fulfill the user requests over the http. A typical example of web application is Hotmail .
4)Web services are web applications that provide services to other applications over the internet. Google search engine’s web service, e.g., allows other applications to delegate the task of searching over the internet to Google web service and use the result produced by it in their own applications
Common Language Runtime(CLR):
Common language runtime is the foundation of the .Net framework.
CLR is a common runtime for all the .net languages.CLR is providing language integration without depending on COM.
CLR can understand only one language i.e. MSIL(Microsoft Intermediate language).
MSIL code will be similar to assembly language syntax.MSIL is platform independent code.
.Net framework is providing set of high level languages to produce MSIL code.
These high level languages(.Net languages) are two types
1 Microsoft .Net languages:
VB.Net,C#.Net,VC++.Net,VJ#.Net..etc,these languages are provided by Microsoft
When we buy .Net framework from Microsoft, it will provide .Net language compilers for thes high level languages.
2 Non Microsoft .Net languages:
Non Microsoft languages which are .Net compatible languages are called third party languages
Ex: cobol.net,fotron.net,python.net
For these languages we have to purchase compilers from vendors.
Understanding Architecture of .NET Framework CLR
Ø Class loader, which loads classes into CLR.
Ø MSIL to native code compiles, this converts MSIL code into native code.
Ø Code manager, this manages the code during execution.
Ø Garbage collector, this performs automatic memory management.
Ø Thread support, which provides multithreading support to applications.
Ø Exception manager, which provides a mechanism to handle the run-time exceptions handling.
Ø Type checker, which enforces strict type checking.
Ø COM marshaler, which allows .NET applications to exchange data with COM applications.
Ø Security engine, this enforces security restrictions as code level security folder level and machine level security using tools provided by Microsoft .NET and using .NET Framework setting under control panel.
Ø Debug engine, which allows developer to debug different types of applications.
Ø Base class library support, which provides the classes (types) that the applications need at run time.
JIT(Just InTime) compiler is the integral part of CLR.When we compile the .Net application language compilers convert high level code into MSIL code and JIT compiler convert MSIL code to Native code,because operating system can under stand only Native code.
Managed code and Unmanaged Code:
The concept of code management is the fundamental principal of the CLR,code that targets the CLR is known as manged code,and code that does not target the CLR is know as unmanged code.
Common Language Specification:
CLS is common Language specification,Microsoft has released a small set of specification that each language should meet to qualify as a .Net compliant language.
Common Type System:
CTS is Common Type System,it is a set of standards.
CTS defines the basic datatypes. Each .net compliant language should map its datatypes to these standard datatype.
For example,CTS defines a typeInt32,an integral datatype of 32 bits(4Bytes),which is mapped by C# through int and VB.Net through its integer data type.
This makes its possible for the 2 languages to communicate with each other. Therefore in .Netframework you have single class called System.Int32 to interpret these variables.
In .Netframework,system.object is the common base type from where all the other types are derived.
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